1. Technical Field
The present invention relates to a heat sink to be used in a liquid cooler, and a method of manufacturing the heat sink, a liquid cooler comprising the heat sink and the use of such a cooler.
2. Background Art
Electronic components are continuously improved. The sizes are reduced and the capacity increased. The ever increasing power density entails that also the cooling of such components needs to be improved.
In EP1175135, there is shown a heat sink in which four corrugated fins are respectively inserted into the four through holes and both ends of a casing are closed with covers by brazing. Forming and inserting the cooling fin adds labour and manufacturing cost.
Also in JP2002-170915 a liquid cooling heat sink in which an inner fin is inserted into the cooling liquid passages for promoting heat transfer of the flow passages is described. However, this construction gives a low heat conductivity, since the heat transfer has to take place via the brazing material, which has low heat conductivity and therefore it is impossible to obtain the low inner thermal resistance required.
In JP, 08-279578 channels are formed by producing a finned structure and closing off the upper openings of the cooling passages and arranging for a header at the end of the channels for the direction of the flow to be reversed. Nothing is said about the method for producing the fins and there is only one cooling channel section.
When extrusion is used to produce a heat sink, the internal cooling channel structure can be manufactured at a reasonable cost, since the number of machining steps can be minimized. There is however a limit to the height and the pitch of the fins which can be processed; therefore, it is difficult to maintain the cooling capacity of a liquid cooler comprising an extruded heat sink.
Thus, there is a need for improved cooling of electronic components. Principally a high cooling performance is desired, by means of which the temperature of electronic components can be kept at a low level. Furthermore, the cooling rate, with regard to the flow rate, is to be maximized. The design shall be simple and the manufacturing thereof must be cost-effective.